/*
 * EAP-WSC peer for Wi-Fi Protected Setup
 * Copyright (c) 2007-2008, Jouni Malinen <j@w1.fi>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Alternatively, this software may be distributed under the terms of BSD
 * license.
 *
 * See README and COPYING for more details.
 */

#include "includes.h"

#include "common.h"
#include "uuid.h"
#include "eap_i.h"
#include "eap_common/eap_wsc_common.h"
#include "wps/wps.h"
#include "wps/wps_defs.h"


struct eap_wsc_data {
        enum { WAIT_START, MESG, FRAG_ACK, WAIT_FRAG_ACK, DONE, FAIL } state;
        int registrar;
        struct wpabuf *in_buf;
        struct wpabuf *out_buf;
        enum wsc_op_code in_op_code, out_op_code;
        size_t out_used;
        size_t fragment_size;
        struct wps_data *wps;
        struct wps_context *wps_ctx;
};


static const char * eap_wsc_state_txt(int state)
{
        switch (state) {
        case WAIT_START:
                return "WAIT_START";
        case MESG:
                return "MESG";
        case FRAG_ACK:
                return "FRAG_ACK";
        case WAIT_FRAG_ACK:
                return "WAIT_FRAG_ACK";
        case DONE:
                return "DONE";
        case FAIL:
                return "FAIL";
        default:
                return "?";
        }
}


static void eap_wsc_state(struct eap_wsc_data *data, int state)
{
        wpa_printf(MSG_DEBUG, "EAP-WSC: %s -> %s",
                   eap_wsc_state_txt(data->state),
                   eap_wsc_state_txt(state));
        data->state = state;
}


static void * eap_wsc_init(struct eap_sm *sm)
{
        struct eap_wsc_data *data;
        const u8 *identity;
        size_t identity_len;
        int registrar;
        struct wps_config cfg;
        const char *pos;
        const char *phase1;
        struct wps_context *wps;

        wps = sm->wps;
        if (wps == NULL) {
                wpa_printf(MSG_ERROR, "EAP-WSC: WPS context not available");
                return NULL;
        }

        identity = eap_get_config_identity(sm, &identity_len);

        if (identity && identity_len == WSC_ID_REGISTRAR_LEN &&
            os_memcmp(identity, WSC_ID_REGISTRAR, WSC_ID_REGISTRAR_LEN) == 0)
                registrar = 1; /* Supplicant is Registrar */
        else if (identity && identity_len == WSC_ID_ENROLLEE_LEN &&
            os_memcmp(identity, WSC_ID_ENROLLEE, WSC_ID_ENROLLEE_LEN) == 0)
                registrar = 0; /* Supplicant is Enrollee */
        else {
                wpa_hexdump_ascii(MSG_INFO, "EAP-WSC: Unexpected identity",
                                  identity, identity_len);
                return NULL;
        }

        data = os_zalloc(sizeof(*data));
        if (data == NULL)
                return NULL;
        data->state = registrar ? MESG : WAIT_START;
        data->registrar = registrar;
        data->wps_ctx = wps;

        os_memset(&cfg, 0, sizeof(cfg));
        cfg.wps = wps;
        cfg.registrar = registrar;

        phase1 = eap_get_config_phase1(sm);
        if (phase1 == NULL) {
                wpa_printf(MSG_INFO, "EAP-WSC: phase1 configuration data not "
                           "set");
                os_free(data);
                return NULL;
        }

        pos = os_strstr(phase1, "pin=");
        if (pos) {
                pos += 4;
                cfg.pin = (const u8 *) pos;
                while (*pos != '\0' && *pos != ' ')
                        pos++;
                cfg.pin_len = pos - (const char *) cfg.pin;
        } else {
                pos = os_strstr(phase1, "pbc=1");
                if (pos)
                        cfg.pbc = 1;
        }

        if (cfg.pin == NULL && !cfg.pbc) {
                wpa_printf(MSG_INFO, "EAP-WSC: PIN or PBC not set in phase1 "
                           "configuration data");
                os_free(data);
                return NULL;
        }

        data->wps = wps_init(&cfg);
        if (data->wps == NULL) {
                os_free(data);
                return NULL;
        }
        data->fragment_size = WSC_FRAGMENT_SIZE;

        if (registrar && cfg.pin) {
                wps_registrar_add_pin(data->wps_ctx->registrar, NULL,
                                      cfg.pin, cfg.pin_len, 0);
        }

        return data;
}


static void eap_wsc_deinit(struct eap_sm *sm, void *priv)
{
        struct eap_wsc_data *data = priv;
        wpabuf_free(data->in_buf);
        wpabuf_free(data->out_buf);
        wps_deinit(data->wps);
        os_free(data->wps_ctx->network_key);
        data->wps_ctx->network_key = NULL;
        os_free(data);
}


static struct wpabuf * eap_wsc_build_msg(struct eap_wsc_data *data,
                                         struct eap_method_ret *ret, u8 id)
{
        struct wpabuf *resp;
        u8 flags;
        size_t send_len, plen;

        ret->ignore = FALSE;
        wpa_printf(MSG_DEBUG, "EAP-WSC: Generating Response");
        ret->allowNotifications = TRUE;

        flags = 0;
        send_len = wpabuf_len(data->out_buf) - data->out_used;
        if (2 + send_len > data->fragment_size) {
                send_len = data->fragment_size - 2;
                flags |= WSC_FLAGS_MF;
                if (data->out_used == 0) {
                        flags |= WSC_FLAGS_LF;
                        send_len -= 2;
                }
        }
        plen = 2 + send_len;
        if (flags & WSC_FLAGS_LF)
                plen += 2;
        resp = eap_msg_alloc(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC, plen,
                             EAP_CODE_RESPONSE, id);
        if (resp == NULL)
                return NULL;

        wpabuf_put_u8(resp, data->out_op_code); /* Op-Code */
        wpabuf_put_u8(resp, flags); /* Flags */
        if (flags & WSC_FLAGS_LF)
                wpabuf_put_be16(resp, wpabuf_len(data->out_buf));

        wpabuf_put_data(resp, wpabuf_head_u8(data->out_buf) + data->out_used,
                        send_len);
        data->out_used += send_len;

        ret->methodState = METHOD_MAY_CONT;
        ret->decision = DECISION_FAIL;

        if (data->out_used == wpabuf_len(data->out_buf)) {
                wpa_printf(MSG_DEBUG, "EAP-WSC: Sending out %lu bytes "
                           "(message sent completely)",
                           (unsigned long) send_len);
                wpabuf_free(data->out_buf);
                data->out_buf = NULL;
                data->out_used = 0;
                if ((data->state == FAIL && data->out_op_code == WSC_ACK) ||
                    data->out_op_code == WSC_NACK ||
                    data->out_op_code == WSC_Done) {
                        eap_wsc_state(data, FAIL);
                        ret->methodState = METHOD_DONE;
                } else
                        eap_wsc_state(data, MESG);
        } else {
                wpa_printf(MSG_DEBUG, "EAP-WSC: Sending out %lu bytes "
                           "(%lu more to send)", (unsigned long) send_len,
                           (unsigned long) wpabuf_len(data->out_buf) -
                           data->out_used);
                eap_wsc_state(data, WAIT_FRAG_ACK);
        }

        return resp;
}


static int eap_wsc_process_cont(struct eap_wsc_data *data,
                                const u8 *buf, size_t len, u8 op_code)
{
        /* Process continuation of a pending message */
        if (op_code != data->in_op_code) {
                wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d in "
                           "fragment (expected %d)",
                           op_code, data->in_op_code);
                return -1;
        }

        if (len > wpabuf_tailroom(data->in_buf)) {
                wpa_printf(MSG_DEBUG, "EAP-WSC: Fragment overflow");
                eap_wsc_state(data, FAIL);
                return -1;
        }

        wpabuf_put_data(data->in_buf, buf, len);
        wpa_printf(MSG_DEBUG, "EAP-WSC: Received %lu bytes, waiting "
                   "for %lu bytes more", (unsigned long) len,
                   (unsigned long) wpabuf_tailroom(data->in_buf));

        return 0;
}


static struct wpabuf * eap_wsc_process_fragment(struct eap_wsc_data *data,
                                                struct eap_method_ret *ret,
                                                u8 id, u8 flags, u8 op_code,
                                                u16 message_length,
                                                const u8 *buf, size_t len)
{
        /* Process a fragment that is not the last one of the message */
        if (data->in_buf == NULL && !(flags & WSC_FLAGS_LF)) {
                wpa_printf(MSG_DEBUG, "EAP-WSC: No Message Length field in a "
                           "fragmented packet");
                ret->ignore = TRUE;
                return NULL;
        }

        if (data->in_buf == NULL) {
                /* First fragment of the message */
                data->in_buf = wpabuf_alloc(message_length);
                if (data->in_buf == NULL) {
                        wpa_printf(MSG_DEBUG, "EAP-WSC: No memory for "
                                   "message");
                        ret->ignore = TRUE;
                        return NULL;
                }
                data->in_op_code = op_code;
                wpabuf_put_data(data->in_buf, buf, len);
                wpa_printf(MSG_DEBUG, "EAP-WSC: Received %lu bytes in first "
                           "fragment, waiting for %lu bytes more",
                           (unsigned long) len,
                           (unsigned long) wpabuf_tailroom(data->in_buf));
        }

        return eap_wsc_build_frag_ack(id, EAP_CODE_RESPONSE);
}


static struct wpabuf * eap_wsc_process(struct eap_sm *sm, void *priv,
                                       struct eap_method_ret *ret,
                                       const struct wpabuf *reqData)
{
        struct eap_wsc_data *data = priv;
        const u8 *start, *pos, *end;
        size_t len;
        u8 op_code, flags, id;
        u16 message_length = 0;
        enum wps_process_res res;
        struct wpabuf tmpbuf;

        pos = eap_hdr_validate(EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC, reqData,
                               &len);
        if (pos == NULL || len < 2) {
                ret->ignore = TRUE;
                return NULL;
        }

        id = eap_get_id(reqData);

        start = pos;
        end = start + len;

        op_code = *pos++;
        flags = *pos++;
        if (flags & WSC_FLAGS_LF) {
                if (end - pos < 2) {
                        wpa_printf(MSG_DEBUG, "EAP-WSC: Message underflow");
                        ret->ignore = TRUE;
                        return NULL;
                }
                message_length = WPA_GET_BE16(pos);
                pos += 2;

                if (message_length < end - pos) {
                        wpa_printf(MSG_DEBUG, "EAP-WSC: Invalid Message "
                                   "Length");
                        ret->ignore = TRUE;
                        return NULL;
                }
        }

        wpa_printf(MSG_DEBUG, "EAP-WSC: Received packet: Op-Code %d "
                   "Flags 0x%x Message Length %d",
                   op_code, flags, message_length);

        if (data->state == WAIT_FRAG_ACK) {
                if (op_code != WSC_FRAG_ACK) {
                        wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d "
                                   "in WAIT_FRAG_ACK state", op_code);
                        ret->ignore = TRUE;
                        return NULL;
                }
                wpa_printf(MSG_DEBUG, "EAP-WSC: Fragment acknowledged");
                eap_wsc_state(data, MESG);
                return eap_wsc_build_msg(data, ret, id);
        }

        if (op_code != WSC_ACK && op_code != WSC_NACK && op_code != WSC_MSG &&
            op_code != WSC_Done && op_code != WSC_Start) {
                wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d",
                           op_code);
                ret->ignore = TRUE;
                return NULL;
        }

        if (data->state == WAIT_START) {
                if (op_code != WSC_Start) {
                        wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d "
                                   "in WAIT_START state", op_code);
                        ret->ignore = TRUE;
                        return NULL;
                }
                wpa_printf(MSG_DEBUG, "EAP-WSC: Received start");
                eap_wsc_state(data, MESG);
                /* Start message has empty payload, skip processing */
                goto send_msg;
        } else if (op_code == WSC_Start) {
                wpa_printf(MSG_DEBUG, "EAP-WSC: Unexpected Op-Code %d",
                           op_code);
                ret->ignore = TRUE;
                return NULL;
        }

        if (data->in_buf &&
            eap_wsc_process_cont(data, pos, end - pos, op_code) < 0) {
                ret->ignore = TRUE;
                return NULL;
        }

        if (flags & WSC_FLAGS_MF) {
                return eap_wsc_process_fragment(data, ret, id, flags, op_code,
                                                message_length, pos,
                                                end - pos);
        }

        if (data->in_buf == NULL) {
                /* Wrap unfragmented messages as wpabuf without extra copy */
                wpabuf_set(&tmpbuf, pos, end - pos);
                data->in_buf = &tmpbuf;
        }

        res = wps_process_msg(data->wps, op_code, data->in_buf);
        switch (res) {
        case WPS_DONE:
                wpa_printf(MSG_DEBUG, "EAP-WSC: WPS processing completed "
                           "successfully - wait for EAP failure");
                eap_wsc_state(data, FAIL);
                break;
        case WPS_CONTINUE:
                eap_wsc_state(data, MESG);
                break;
        case WPS_FAILURE:
        case WPS_PENDING:
                wpa_printf(MSG_DEBUG, "EAP-WSC: WPS processing failed");
                eap_wsc_state(data, FAIL);
                break;
        }

        if (data->in_buf != &tmpbuf)
                wpabuf_free(data->in_buf);
        data->in_buf = NULL;

send_msg:
        if (data->out_buf == NULL) {
                data->out_buf = wps_get_msg(data->wps, &data->out_op_code);
                if (data->out_buf == NULL) {
                        wpa_printf(MSG_DEBUG, "EAP-WSC: Failed to receive "
                                   "message from WPS");
                        return NULL;
                }
                data->out_used = 0;
        }

        eap_wsc_state(data, MESG);
        return eap_wsc_build_msg(data, ret, id);
}


int eap_peer_wsc_register(void)
{
        struct eap_method *eap;
        int ret;

        eap = eap_peer_method_alloc(EAP_PEER_METHOD_INTERFACE_VERSION,
                                    EAP_VENDOR_WFA, EAP_VENDOR_TYPE_WSC,
                                    "WSC");
        if (eap == NULL)
                return -1;

        eap->init = eap_wsc_init;
        eap->deinit = eap_wsc_deinit;
        eap->process = eap_wsc_process;

        ret = eap_peer_method_register(eap);
        if (ret)
                eap_peer_method_free(eap);
        return ret;
}
